The present invention relates to devices for treating fluids, and particularly to fluid treatment devices for mixing first and second fluids. Some embodiments of the present invention relate to fluid treatment devices for mixing matrix materials with fluids carrying analytes so that, after the mixture is placed on substrates, analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF/MS) may be performed.
In broad general terms analytical chemistry is concerned with separating, identifying, and quantifying the relative amounts of the chemical components of a sample. Frequently, samples are subjected to a number of successive analytical techniques in order to advance the analysis of the components contained therein. This strategy of utilizing successive analytical techniques can be useful in analyzing any type of chemical component, but it is particularly helpful when the components to be analyzed are biological molecules, such as polypeptides, proteins, lipids, polynucleotides, and/or polysaccharides. For example, it is common to initially subject a sample containing biological molecules to a chromatography technique in order to separate the constituent molecules of the sample into a number of liquid fractions collected from the effluent of the chromatography system (e.g. effluent from electrically driven devices, such as CE and CEC devices, or pump driven devices, such as capillary LC and micro-LC). Thereafter, each fraction can be subjected to a subsequent analytical technique in order to obtain additional information about the biological molecules contained therein. Examples of analytical techniques the fractionated biological molecules can be subjected to include, but are not limited to, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance.
However, it should be appreciated that prior to analyzing the constituents of a fraction with a subsequent analytical technique, it is frequently desirable to alter the chemical/physical characteristics of the liquid containing the biological molecules of interest. For example, it may be desirable to introduce an additional substance into the liquid containing the molecules of interest to serve as a matrix material for subsequent MALDI mass spectrometry analysis, or the additional substance may be introduced to alter the pH, density, and/or ionic strength of liquid in order to prepare it for further analysis. Accordingly, an apparatus and method for altering the chemical/physical characteristics of a liquid containing a substance of interest is desirable.